RESULTS AND CONCLUSIONS
1. Fuel Pressure Correct - Fuel Discharged Freely
If the fuel pressure in the supply line is found to
be correct and also fuel is freely discharged from the relief valve, the
absence of pulsations is probably caused by the rotor remaining stationary.
The ignition should, therefore, be switched off, and the metering distributor
removed. The drive couplings should then be examined for signs of breakage. If
drive coupling is intact and rotor revolves, remove unit for examination.
Important
It is essential to comply with the engine
manufacturer’s instructions to ensure correct timing when the metering
distributor is re-fitted to the engine. See refitting instructions.
2. Fuel Pressure Zero - No Fuel Discharged
If no fuel is discharged from the relief valve, and
the pressure gauge reading is zero, the fuel pump should be removed from the
vehicle to enable the pump element and drive coupling to be examined.
3. Fuel Pressure Cannot be Adjusted
If the relief valve cannot be adjusted to give
correct pressure readings, either the relief valve or the pump motor is
faulty.
The pump motor is then checked, see workshop instructions. If the pump is
shown to be operating satisfactorily, the relief valve is faulty and should be
renewed.
Important
The setting of the new valve should be checked,
before the ‘T’ piece and the pressure gauge are removed. After the relief
valve has been adjusted or replaced, the fuel pressure in the supply line is
adjusted to 100-110 psi (689.50-758.50 kN/m2). The return-
to-supply pipe is then reconnected to the relief valve. The ignition is
switched on again, and the pressure gauge reading is noted. If this reading is
higher than was previously obtained, the return-to-supply pipe is faulty
(being either blocked or “kinked”). The pipe should, therefore, be
serviced or renewed. When the test is completed, the LT cable is reconnected
to the ignition coil.
REMOVING METERING UNIT FROM ENGINE
Before removing the metering unit from the engine
set static ignition timing.
(i) Remove ignition distributor cap and check that rotor arm is pointing
towards No. 1 electrode (cylinder) and contacts have just opened.
(ii) Disconnect battery earth lead.
(iii) Disconnect injector pipes at injectors.
(iv) Disconnect vacuum pipe at metering unit.
(v) Disconnect and blank off the fuel inlet pipe, and drain pipe.
Note: It is advisable to use hose clamps to prevent loss of fuel.
(vi) Disconnect the cold start cable (to excess fuel lever) at the metering
unit.
(vii) Unscrew the two nuts securing drive housing to engine block pedestal.
(viii) Remove pedestal from engine block complete with ignition distributor,
metering unit and injector pipes.
(ix) Remove three securing studs and separate metering unit from pedestal and
drive housing. Remove drive coupling.
REFITTING METERING UNIT TO ENGINE
When refitting the metering unit, ensure that it is
correctly timed to the engine. The rotor arm electrode should point towards
No. 1 electrode in the ignition distributor cap, with the contact-breaker
points just open.
(i) Renew ‘O’ ring on engine block pedestal.
(ii) Align scribe marks on rotor and metering unit fixing flange face.
(iii) Place drive coupling in position.
(iv) Refit metering unit to engine block pedestal. (Before refitting to
engine, re-connect cold start cable to metering unit). Re-assemble to engine
in reverse order to removal instructions.
(v) Bleed injectors.
HOW TO CHECK METERING UNIT TO ENGINE TIMING
Turn engine until correct timing mark on crankshaft
pulley is aligned to pointer with No. 1 cylinder on compression. Remove No. 6
outlet union from metering unit body and check that rotor port is showing
partially open.